Si-nanowire-based multistage delayed Mach–Zehnder interferometer optical MUX/DeMUX fabricated by an ArF-immersion lithography process on a 300  mm SOI wafer

Abstract

We report good phase controllability and high production yield in Si-nanowire-based multistage delayed Mach-Zehnder interferometer-type optical multiplexers/demultiplexers (MUX/DeMUX) fabricated by an ArF-immersion lithography process on a 300 mm silicon-on-insulator (SOI) wafer. Three kinds of devices fabricated in this work exhibit clear 1×4 Ch wavelength filtering operations for various optical frequency spacing. These results are promising for their applications in high-density wavelength division multiplexing-based optical interconnects.

Silicon Photonic Integrated Circuits for Wavelength-Division Multiplexing Applications

“…If a broadband modulator, such as Mach-Zehnder modulator (MZM), is used, the WDM circuit would simply consist of multiple modulators, followed by wavelength multiplexers. The multiplexers can be realized using AWGs [30][31][32][33][34][35][36], echelle gratings [37][38][39], cascaded Mach-Zehnder interferometers (MZIs) [40][41][42], and microring/microdisk resonators [43][44][45][46][47][48][49]. A WDM circuit, including multi-channel silicon MZMs together with second-order ring filters, is shown in Fig.…”

1 × 4 Channel Si-Nanowire Microring-Assisted Multiple Delayline-Based Optical MUX/DeMUX

“…2. Based on the coupled mode theory and transfer matrix method [7], [8], we calculated the amplitude and phase characteristics of the proposed optical DeMUX structure when only the MRRs are excluded in Fig. 1.…”

“…[4] consists of three DMZIs with 3-dB optical couplers, while the Conv-2 scheme based on Refs. [6] and [7] is composed of 21 DMZIs with different optical coupling ratios and proper PSs. In order to fairly make a comparison the spectral flatness for three kinds of optical DeMUXs, all device parameters were optimized to make the spectral shape as flat as possible, minimizing the spectral XT at around WDM Ch grids.…”

“…1, the proposed scheme uses many optical couplers in the split, delayline and coupling regions. Usually, a waveguide-type coupler such as a DC has an intrinsic wavelength sensitive coupling efficiency, which causes the spectral response to be degraded, as reported in [7]. In the split region, using a 1 × 2 MMI coupler [21], [22] would guarantee low EL and only a little wavelength sensitivity on the coupling behavior.…”

“…Two kinds of schemes were reported for obtaining boxlike spectral response. A 1 × 4 channel (Ch) flatband DeMUX by doubling the multistage DMZIs was recently reported [6], [7]. However, spectral flatness was accompanied by an increase in the number of DMZIs with several optical path lengths and optical couplers, which inherently makes a device size larger.…”